The court has agreed to hear initial arguments in the case on Oct. 22.

Here are next steps and what it could mean for Tianqi’s efforts to complete a deal.

WHY WAS THE LAWSUIT FILED?

The lawsuit was filed by controlling shareholder and former SQM chairman Julio Ponce Lerou, via his investment vehicles Pampa Calichera, Potasios de Chile and Global Mining, collectively known as the Pampa Group. Ponce has been a key figure in SQM since it was privatized in the 1980s under his former father-in-law, dictator Augusto Pinochet.

The lawsuit said a previous anti-trust court decision clearing the deal did not give adequate time for shareholders to review an agreement between Tianqi and regulators.

The agreement aimed to limit the exchange of information between Tianqi and SQM, and curbed Tianqi’s role on SQM’s board.

Ponce objects to how the agreement was struck and what it does to limit competitive risks. In the filings, his Pampa Group said it feared the transaction would give Tianqi, a top competitor, “unrestricted access” to all of the Chilean miner’s “confidential and sensitive information.”

Tianqi is also in a joint venture with No. 1 lithium producer Albemarle Corp in Australia, where together they own the world’s biggest lithium mine.

The Pampa Group said it was especially concerned that Tianqi’s relationship would allow Albemarle, a close neighbor in Chile’s lithium-rich Salar de Atacama, to obtain its business and operating secrets.

HAS THIS HAPPENED BEFORE IN BUSINESS DEALS IN CHILE?

Chile’s Constitutional Court has seen relatively few cases like this one, challenging decisions made by the country’s 15-year old antitrust court.

Francisco Aguero, a former director of the University of Chile’s Center on Regulation and Competition, said the Constitutional Court had not previously contradicted findings by the antitrust court.

But he said the Constitutional Court - which has recently been bogged down by an increased caseload - may have been a good choice if Ponce’s intent was to stall the sale of Nutrien’s stake to Tianqi.

“This could really paralyze this process,” he said, adding that it was a “procedural triumph” for Ponce to have obtained a quick audience with the court.

“It’s worth mentioning that Ponce Lerou, in past cases, has done well in the Constitutional Court,” he said.

WHAT ARE THE POSSIBLE OUTCOMES?

Five Constitutional Court judges will hear arguments from lawyers for all parties in the case on Oct. 22. They can then decline to hear the case further or opt for a fuller hearing involving 10 judges.

If they go ahead, the judges meet again behind closed doors, before issuing their final decision in writing at a later date. While the process could be expedited, it gave no timeline on a ruling.

They can either declare the contested agreement constitutional and lift the suspension, allowing the deal to proceed, or declare it unconstitutional. In that case, all parties would have to return to the antitrust court and forge another agreement, or overturn the deal if they cannot.

The Constitutional Court’s ruling is final and cannot be appealed to any higher Chilean court.

WHERE DOES NUTRIEN STAND ON THIS?

The Canadian fertilizer company - formerly Potash Corp of Saskatchewan - must offload its stake in SQM to meet regulatory requirements following its merger with a rival fertilizer company to create Nutrien.

Chinese and Indian regulators have given Nutrien until April 19, 2019 to sell its shares in SQM, which is also an important producer of agricultural chemicals. The clock is ticking.

Nutrien told the Constitutional Court that the “real objective” of Ponce’s suit was to block the deal and force Nutrien to “miss its deadline with Indian and Chinese regulators.”

“Blocking this deal could cost Nutrien hundreds of millions of dollars,” it said.

WHAT IS TIANQI’S POSITION?

In a hearing before Chile’s antitrust court, a lawyer for Tianqi said Ponce was seeking to block the deal to maintain his own dominance at SQM.

Ponce stepped down as president of SQM in 2015 but retained his shares in the company.

“If this is not approved, Nutrien would have to sell its stake on the bourse, atomizing the holding,” said lawyer Claudio Lizana.

If the shares were sold piecemeal, Ponce would not have to contend with another “weighty shareholder,” Lizana said.

Tianqi on Friday told Reuters that Ponce’s actions were “desperate”.

“No one has ever questioned the ability of the FNE (Chilean regulator) to reach out-of-court settlements in such issues,” it said.